This invention relates to a microwave oven comprising an oven cavity, a microwave source for feeding HF energy into the cavity, a power device for the supply of power to the microwave source and a fan for cooling the components of the power device, including the microwave source, the power device microwave source and the fan are combined into a unit, the so called power module, comprising a substantially closed envelope having an air inlet, an air outlet, an input for the AC supply voltage and an output for HF power coupled to the oven cavity. The envelope has an air channel between the air inlet and the air outlet for producing a forced cooling air stream by means of the fan, the components to be cooled being arranged in the path of the cooling air stream.
GB 2 003 007 discloses a power module for microwave ovens of the kind set forth in the first paragraph. The power module comprises a tubular housing containing a cooling fan, a microwave source and a power supply positioned in that order between an air inlet at one end of the tubular housing and an air outlet at the other end of the housing. The microwave source is situated at the midpoint of the housing and only the output antenna projects from the housing.
By means of a power module according to the above, it is achieved that the assembly of the microwave oven is less complicated and time consuming than when the components are mounted together directly in an oven. The power modules are tested before they are inserted in the oven, so that the risks of malfunctions of the oven when assemblyed are reduced almost to zero the use of this power module concept. However, the power module according to said British application is restricted in its use to one or possibly a few oven constructions due to the location of the microwave source and the output antenna.